METHOD FOR CONTROL OF THE CURL OF PAPER IN THE DRYER SECTIONOF A PAPER MACHINE AND PAPER OR BOARD MACHINE

摘要

A method in the dryer section of a paper or board machine for control of the curl of paper uses steam treatment and/or moistening of the paper web. The operations are carried out in a number of stages and/or the web temperature is lower than 85.degree.C and/or when the dry solids content of the web is in the range of K1 to K2, wherein K1 = ultimate dry solids content -7% and K2 = ultimate dry solids content +3%. A paper or board machine, comprises at least a headbox, a former, a press, and a dryer sectio n, in which steam boxes or moistening devices are employed for control of the curl. At least two of said curl regulation devices to achieve regulation of the curl in a number o f stages, and/or fitted to operate in an area in which the web temperature is lower than 85.degree.C and/or the dry solids content of the web is in a range of K1 to K2.